'Masterpiece' was Hamilton's line of presentation watches, intended for just this purpose - honoring retirees, etc. I can't make out the hallmark, but they were often solid gold. That particular one looks like a Courtney,which is a 14k watch, with Hamilton's highly regarded 22j 770 movement.
That model being presented in 1969 is odd, because it doesn't appear in the catalogs after 1960,(p29) but then perhaps Hamilton made watches available to companies as presentations that they didn't make available to jewelers. I know that, for example, there are two particular Lord Elgins in stainless steel cases that I've only ever seen as presentations given by either US Steel, or Jones and Loughlin Steel.
Beautiful watch, and a wonderful piece of family history!